High current capacity switching device

ABSTRACT

Confronting and slidable roll holders include lateral supports between which a compression spring is arranged for forcing the rolls carried by the roll holders towards each other by pushing the supports apart. The rolls are thus maintained in contact with rails interspersed between the rolls and the roll holders are maintained in position against each other by link rods formed of insulation material.

United States Patent [1 1 Cottereau Sept. 2, 1975 [54] HIGH CURRENT CAPACITY SWITCHING 3,648,003 3/1972 Wiktor 200/277 X DEVICE 3,812,309 5 1974 Ahrano 200/277 x [75] Inventor: Grard Cottereau, Tarbes, France FOREIGN PATENTS OR APPLICATIONS 73 Assigneez s i Generale de Constructions 43-22848 8/1968 Japan ZOO/277 Electriques et Mecaniques 258,536 3/1928 Italy ZOO/277 (ALSTIIOM), Paris, France Primary Examiner Robert K. Schaefer [22] Flled' July 1974 Assistant ExaminerWilliam J. Smith [21] Appl. No.: 489,023 Attorney, Agent, or Firm-Sughrue, Rothwell, Mion,

Zinn and Macpeak [30] Foreign Application Priority Data Aug. 7, 1973 France 73.28848 ABSTRACT Confronting and slidable roll holders include lateral [52] U.S. Cl 200/277, 2020/48 R,200/248, supports between which a Compression Spring is 5 ZOO/290 ranged for forcing the rolls carried by the roll holders [51] f 9 2 Holh 1/30 Holh 238 towards each other by pushing the supports apart. The [58] held of Search 2 1 rolls are thus maintained in contact with rails inter- 200/250 2 spersed between the rolls and the roll holders are maintained in position against each other by link rods [56] References cued formed of insulation material.

UNITED STATES PATENTS 2,297,772 10/1942 Johnson 200/277 x 5 Clams 5 Drawmg Flgures PATENTED 21975 SHEET 1 BF 3 1 HIGH CURRENT CAPACITY SWITCHING DEVICE BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile contact device for a high current circuit breaker, and more particularly, to an arrangement for biasing the rolls in contact with respective sides of fixed rails forming the ciruit breaker conductors.

2. Description of the Prior Art It is well known to manufacture circuit breakers which use a conductive roll driven in a linear movement above two rails which are also conductive, one of which is interrupted by an insulating portion. The electrical current arrives through the uninterrupted rail, passes through the roll and leaves through the interrupted rail. As the rail is interrupted, according to whether the roll is on one side of the interruption or on the other, the current leaves on one side of the rail or the other, thus forming opposite directions of conductivity. In a first phase, the roll is positioned in the required direction, then, in a second phase only, the current is permitted to pass, because the roll must not be moved under tension, on account of the high current passing through the roll. The current directed in this manner makes it possible to feed an electrical charge in a direct or reverse direction, thus permitting by way of such a mechanism, a circuit breaker useful in the railway industry for operating the rail car in forward or reverse gear and for changing over from a driving operation to a braking operation.

In order to reduce the electrical resistance of the contacts and to thus increase the power of current passing through them, a second roll parallel to the first is added, with the second roll being arranged beneath the rails, whereas the first roll is arranged above them.

These two rolls must be brought back or biased towards each other in order to insure the necessary pressure for passing the current through the four contact points between the rolls and the multiple rails.

Reference to FIG. 1 illustrates in somewhat schematic, perspective form the basic components of a circuit breaker of the type to which the present invention has application, the circuit breaker consisting of two conductive rails, l and 2, which may be made of copper, on which rolls 3 and 4 rotate as they move linearly relative to the axis of the rails, the rolls 3 and 4 being conductive and also preferably formed of copper. Rail 2 is provided with an electrical break by arranging a portion 5 formed of an electrically insulating material as a section of the rail, however, the insulating portion insuring mechanical continuity of rail 2. Known technique for such devices employs tension springs 6 and 7 to maintain the rolls in contact with respective sides of the two conductor rails I and 2, that is, the upper and lower surfaces of those rails. The current to be switched enters rail 1 as indicated at arrow A and passes through the rails and rolls in the direction of the arrows and leaves at B or at C according to whether the rolls 3 and 4 are in the position shown in continuous lines or in the position shown by the discontinuous lines. It should be observed that the current in the rolls follows the paths parallel and in the same direction, thus having the consequence of generating electrodynamic forces employed for reinforcing the pressure of the rolls on the rails and thus avoiding the damaging of the contacts or welding in case of a short circuit or of high overloads.

FIG. 2 shows an embodiment of a double circuit breaker to which the present invention has application and which comprises four rails 1, 2, l 2, two of which have their conductivity interrupted by insulation portions 5 and 5. For each pair of rolls, only the rolls 3 and 3' are visible. The current comes from the pole, follows the rail 1, roll 3 (its underlying companion roll not shown), the rail 2, the point B and reaches a load 8, through which it passes in the direction of the arrow before closing again on the pole through point C, rail 1', roll 3 (as well as the underlying roll not shown) and rail 2'.

A servo-motor 9 controlling a lever 10 which pivots on axis 11 makes it possible to arrange the rolls 3 and 3' in the position in which they areshown in FIG. 2 or in a reverse position in which the roll 3 is above the insulating portion 5 and the roll 3' is above the insulating portion 5. In that reverse position, the pole closes on the pole, passing through the load 8 in the opposite direction to the arrow. It should be observed that according to the invention, the drive arms of the rolls l2 and 13 controlled by lever 10 are only two in number for the pair of rolls 3 and 4.

SUMMARY OF THE INVENTION The present invention resides in producing the biasing pressure acting on the pair of rolls through a single compression spring. Preferably, a carriage supporting the two rolls acts as a seat for the single compression spring, and being driven in a linear manner by means of two drive elements arranged symmetrically in relation to the center of the carriage.

The object of the present invention is the production of a switching device for high current comprising at least one pair of conductive rails, one of which is interrupted by an insulating portion, at least two conductive contact rolls arranged on respective sides of a pair of rails and which may be moved along the rails while being pressed against respective rails by means tending to bias the rolls towards each other. The improvement resides in the use of two identical roll holders, each provided with a support and a compression spring acting longitudinally on the supports in a direction which tends to pull the supports apart from each other and bias the rolls in contact with respective sides of the rails.

According to one aspect of the invention, the two roll holders are maintained in lateral confronting fashion and assembled into a carriage by means of two link rods which are arranged on respective sides of the roll holder supports and link the holders together.

According to another aspect of the invention, the link rods are fixed to each other such that movement of the link rods results in movement of the carriage along the rails.

With reference to the accompanying diagrammatic FIGS. 15, which' provide an example of implementation of the present invention, such example is given purely by way of an illustration and has no limiting character and will be described hereinafter. The same elements within the several figures bear the same reference numerals.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagrammatic perspective view of a circuit breaker having two rolls and two rails with tension spring indicating the biasing acting through the rollers on the rails.

FIG. 2 is a schematic, operating diagram of a double circuit breaker (reversing switch) of the prior art, having four rolls and four rails, the control means and its load.

FIG. 3 is a diagrammatic, elevational view, partially cut away, of the switch contact device for the circuit breaker in accordance with the present invention.

FIG. 4 is a sectional view of the device of FIG. 3 taken about line IVIV.

FIG. 5 is an exploded perspective view of a roll holder, its compression spring and a link rod forming a part of the circuit breaker contact device in accordance with the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT With reference to FIGS. 3, 4 and 5, the contact device involves a carriage which is composed of two roll holders and 21 which are of identical construction, reversed in relation to each other and positioned in vertical confronting fashion such that support 23 which extends at right angles from the vertical upright 22 underlies support 25 which extends at right angles from the opposite upright 26 with a vertical spacing between the supports. The supports 23 and 25 act as a seat for the compression spring 27 whose return force is exerted against the supports 23 and 25. The roll holders are provided with flanges 18, 18, 19, 19 which are designed to rotatably support rolls 3 and 4, the axle ends being fixed to the flanges. Each roll 3 and 4 is adapted to rotate about its axle 14 by means of ball bearings 15. An insulating ring 16 and an insulating Washer 17 electrically insulate the end of axle 14. The force exerted by the spring tends to force the flanges towards each other. However, the rolls 3 and 4 which ride on the upper and lower faces of rails l and 2 prevent this tendency and the single spring therefore makes it possible to insure a force between the rolls 3 and 4 at their contact lines and rails l and 2, this biasing pressure being of sufficient magnitude and being equally distributed along the lines of contact between rolls 3 and 4 and the rails 1 and 2. Each of the roll holders further comprise bosses as at 28, 29, while to each side of the spring supports 23 and 25, there extends rectangular projections 24 which along with the connecting portion of the roll holders 20 and 21 for flanges 18-18, 19-19, form abutments for respective ends of upper and lower slots 32 and 33 for link rods 30 and 31. The link rods 30 and 31 are in the form of rectangular strips of an electrical insulating material such as phenoplast paper. Their structure is roughly that of a parallelepiped channeled at two places as at 32-33 to avoid contact with the rolls, and to maintain the lateral position of the roll holders 20 and 21 as well as to maintain these members in longitudinal confronting position with the supports 23 and 25 in alignment with the axis of the compressed coil spring 27. Fixtures, not shown, arranged on the link rods, are provided for driving the carriage in a linear movement along the rails to effect the desired switching action.

The roll holders 20 and 21 may be made ofa molded or mechanically welded metal part, stamped or otherwise formed. The identical nature of the parts constituting the carriage simplifies the operation inherent to the manufacturing thereof, reduces the cost of the device, and reduces the cost of implementing the same.

The device which is the object of the invention may be used in all cases where the pressure of the two rolls is to be insured against two parts which are perpendicular to the same. Of course, the illustrated application of the invention resides in its application to electrical contact particularly for circuit breakers employed in the railway industry for heavy current interruption.

While the invention has been particularly shown and described with reference to a preferred embodiment thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.

What is claimed is:

1. In a switching device for high currents including at least one pair of conductive rails, one of which is interrupted by an insulating portion, at least two conductive contact rolls arranged on opposite sides of the pair of rails and movable by rotation along the rails and being pressed against the rails by means biasing the rolls towards each other, the improvement wherein:

said biasing means comprises two identical roll holders oppositely oriented and carrying at one end one of said rolls, compression spring supports on said roll holders, and a compression spring arranged between said rails and sandwiched between respective supports to bias said supports away from each other and said rollers towards each other and in contact with said rails.

2. The switching device according to claim 1, further comprising: link rods arranged on respective sides at said roll holder supports for maintaining said roll holders in a lateral assembly forming a carriage movable longitudinally relative to the rails.

3. The switching device according to claim 2, wherein: said link rods each include means for controlling the linear movement of said carriage along said rails.

4. The switching device according to claim 2, wherein: said link rods are made of an electrically insulating material.

5. The switching device according to claim 2, wherein: each roll holder includes a vertical upright, a pair of flanges integral with said upright at one end thereof, for rotatably supporting a roll by means of an axle extending between said flanges, said support extending at right angles from said upright, at the opposite end thereof from said flanges for seating one end of said compression spring, in rectangular projections extending outward to the side of said support in line with said flange, and wherein said link rods comprise strips of insulation material having recessed upper and lower edges and receiving respectively, portions of said flanges and said rectangular projections for limiting longitudinal movement of one roll holder with respect to the other and maintaining the compression spring seat in alignment for receiving said compression spring. l 

1. In a switching device for high currents including at least one pair of conductive rails, one of which is interrupted by an insulating portion, at least two conductive contact rolls arranged on opposite sides of the pair of rails and movable by rotation along the rails and being pressed against the rails by means biasing the rolls towards each other, the improvement wherein: said biasing means comprises two identical roll holders oppositely oriented and carrying at one end one of said rolls, compression spring supports on said roll holders, and a compression spring arranged between said rails and sandwiched between respective supports to bias said supports away from each other and said rollers towards each other and in contact with said rails.
 2. The switching device according to claim 1, further comprising: link rods arranged on respective sides at said roll holder supports for maintaining said roll holders in a lateral assembly forming a carriage movable longitudinally relative to the rails.
 3. The switching device according to claim 2, wherein: said link rods each include means for controlling the linear movement of said carriage along said rails.
 4. The switching device according to claim 2, wherein: said link rods are made of an electrically insulating material.
 5. The switching device according to claim 2, wherein: each roll holder includes a vertical upright, a pair of flanges integral with said upright at one end thereof, for rotatably supporting a roll by means of an axle extending between said flanges, said support extending at right angles from said upright, at the opposite end thereof from said flanges for seating one end of said compression spring, in rectangular projections extending outward to the side of said support in line with said flange, and wherein said link rods comprise strips of insulationn material having recessed upper and lower edges and receiving respectively, portions of said flanges and said rectangular projections for limiting longitudinal movement of one roll holder with respect to the other and maintaining the compression spring seat in alignment for receiving said compression spring. 